This FIRST
AMENDMENT TO CREDIT AGREEMENT, dated as of March 25, 2009 (this
Amendment), among (i) AFFILIATED
MANAGERS GROUP, INC., a Delaware corporation (the Borrower),
(ii) the undersigned Lenders (as defined below), and (iii) BANK OF AMERICA, N.A. (Bank of America),
as administrative agent for the Lenders (in such capacity, the Administrative
Agent), amends certain provisions of the certain Third Amended and
Restated Credit Agreement, dated as of November 27, 2007 (as amended,
restated, supplemented or otherwise modified from time to time, the Credit
Agreement), among the Borrower, the several banks and other financial
institutions from time to time party thereto (the Lenders), the
Administrative Agent, The Bank of New York Mellon (as successor by merger to
The Bank of New York), JPMorgan Chase Bank, N.A. and U.S. Bank National
Association, as Co-Syndication Agents, Calyon New York Branch and RBS Citizens,
National Association, as Co-Documentation Agents. Any capitalized term used herein and not
defined shall have the meaning assigned to it in the Credit Agreement.